6. Food And Soil.

6. Food And Soil

Soil Ch 9:

Soil: the foundation for agriculture
Land devoted to agriculture covers 38% of Earth’s land Agriculture = practice of raising crops and livestock for human use and consumption Cropland = land used to raise plants for human use Rangeland or pasture = land used for grazing livestock Soil = a complex plant-supporting system Consists of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms It is a renewable resource that can be depleted

Agriculture arose 10,000 years ago
Different cultures independently invented agriculture The earliest plant and animal domestication is from the “Fertile Crescent” of the Middle East Wheat, barley, rye, peas, lentils, onions, goats, sheep

Importance of Soil Provides nutrients Recycles/filters water
Stores water Soil is the basis of life on Earth… Plants get nutrients from soil and plants provided glucose and oxygen (producers)

Traditional agriculture
Agriculture allowed people to settle in one place Populations increased Leading to more intensive agriculture Traditional agriculture = biologically powered Uses human and animal muscle power Hand tools, simple machines Subsistence agriculture = families produce only enough food for themselves Polyculture = different crops are planted in one field

Industrialized agriculture
Industrialized agriculture = uses large-scale mechanization and fossil fuels to boost yields Also uses pesticides, irrigation, and fertilizers Monoculture = uniform planting of a single crop Green revolution = new technology, crop varieties, and farming practices were introduced to developing countries Increased yields and decreased starvation Created new problems and worsened old ones

Soil as a system Soil consists of mineral and organic matter, air, and water Dead and living microorganisms Decaying material Bacteria, algae Habitat for earthworms, insects, mammals, reptiles, and amphibians Since soil is composed of interacting living and nonliving matter, it is considered an ecosystem

Soil formation is a slow process
Parent material = the base geologic material of soil Lava, volcanic ash, rock, dunes Bedrock = solid rock comprising the Earth’s crust Weathering = processes that form soil Physical (mechanical) = wind and rain; no chemical changes in the parent material Chemical = parent material is chemically changed Biological = organisms produce soil through physical or chemical means Humus = spongy, fertile material formed by partial decomposition of organic matter

Terms associated with creation of soil
Infiltration Downward movement of water through the soil Leaching Dissolving of minerals and organic matter in upper layers carrying them to lower layers ***soil type determines degree of leaching and infiltration

Key processes in soil formation
Key processes in forming soil: weathering and the accumulation and transformation of organic matter They are influenced by the following factors: Climate: soils form faster in warm, wet climates Organisms: plants and decomposers add organic matter Topography: hills and valleys affect exposure to sun, wind, and water Parent material: influences properties of resulting soil Time: soil can take decades to millennia to form

Soil Horizons Soil Horizon: a series of zones in a mature soil that each have a distinct texture and composition that varies wit different soil types Soil Profile: A cross sectional view of the soil horizon Mature soils generally have at least 3 of the possible horizons (Top) O A B C R (Bottom) On All Birthdays Cupcakes Rule

Soil Horizons O horizon (surface litter) A Horizon (Topsoil layer)
Uppermost\organic matter (leaves, twigs, crop waste, animal waste, organic matter) Dark, crumbly material that results from decomposition of organic matter Brown or black A Horizon (Topsoil layer) Porous mix of HUMUS and some inorganic particles (weathered rock) Holds water and nutrients for plants *** O and A are anchored by vegetation B Horizon (subsoil) Composed of inorganic minerals Broke down rock (clay, silt, sand/gravel) Receives all minerals leached out of A horizon as well as organic material that is washed down from the topsoil above C Horizon (parent material) Large pieces of rock that have not undergone much weathering R Horizon (Bedrock Layer) Solid bedrock

Soil Textures-3 major divisions
Clay Smallest, very fine, extremely compact, feels sticky Less than 0.002mm in diameter, easily stick to each other Little room between particles to store water Silt mm in diameter Feels smooth, holds water well, resists filtration Sand mm in diameter Coarsest particle, too large to stick together Creates soil with large pores, water filter through **Gravel 2.0 mm and larger Does not hold water well

Increasing percentage sand
100%clay Increasing percentage silt percentage clay 20 40 60 80 100%sand 100%silt Increasing percentage sand sandy clay silty silty clay loam silt sandy clay loamy sand Gravel 2-64 mm Sand mm Silt mm Clay less than mm Soil Texture Triangle

Loamy Soil composed of roughly the same amount of all three textures (clay, silt, sand) and organic matter Loose and rich When you squeeze it, forms a ball that crumbles when poked Good at absorbing and storing water Best for plant growth

Soil Porosity Measure of the volume of pores or air spaces per volume of soil AND average distance between those spaces Fine particles help retain water (precipitation goes into pores) Large particles help create air spaces for filtration Contain varying amounts of air (N and O) and water Porous soil Many pores Can hold more water Non porous soil Not a lot of spaces Cannot hold much water

Soil Permeability Rate at which water and air move through the soil
Sand High permeability Water moves through quickly Filters water Clay Low permeability Water moves through slowly Retain water

Soil structure and pH Soil structure = a measure of soil’s “clumpiness” A medium amount of clumpiness is best for plants Repeated tilling compacts soil, decreasing its water-absorbing capabilities Soil pH = affects a soil’s ability to support plant growth Soils that are too acidic or basic can kill plants pH influences the availability of nutrients for plants

Regional differences in soils affect agriculture
In rainforests the nutrients are in plants, not the soil Rain leaches minerals and nutrients, reducing their accessibility to roots Rapid decomposition of leaf litter results in a thin topsoil layer with little humus Swidden agriculture = traditionally used in tropical areas After cultivation, a plot is left to regrow into forest Temperate prairies have lower rainfall and less nutrient leaching

Geology Ch 2: 33-46

Geothermal energy powers Earth’s systems
Other sources of energy include: The moon’s gravitational pull Geothermal heat powered by radioactivity Radioisotopes deep in the planet heat inner Earth Heated magma erupts from volcanoes Drives plate tectonics Warm water can create geysers

Geology Physical processes at and below the Earth: Shape the landscape
Lay the foundation for environmental systems and life Provide energy from fossil fuels and geothermal sources Geology = the study of Earth’s physical features, processes, and history A human lifetime is just the blink of an eye in geologic time

Our plant consists of layers
Core = solid iron in the center Molten iron in the outer core Mantle = less dense, elastic rock Aesthenosphere: very soft or melted rock Area of geothermal energy Crust = the thin, brittle, low- density layer of rock Lithosphere = the uppermost mantle and the crust

Plate tectonics Plate tectonics = movement of lithospheric plates
Heat from Earth’s inner layers drives convection currents Pushing the mantle’s soft rock up (as it warms) and down (as it cools) like a conveyor belt The lithosphere is dragged along with the mantle Continents have combined, separated, and recombined over millions of years Pangaea = all landmasses were joined into 1 supercontinent 225 million years ago

Earth’s crust is created and destroyed
Divergent plate boundaries Magma rises to the surface Pushing plates apart Creating new crust Has volcanoes and hydrothermal vents Transform plate boundaries Two plates meet, slipping and grinding Friction spawns earthquakes along strike-slip faults

Tectonic plates can collide
Convergent plate boundaries = where plates collide Subduction = the oceanic plate slides beneath continental crust (e.g. the Cascades, Andes Mountains) Magma erupts through the surface in volcanoes Continental collision = two plates of continental crust collide Built the Himalaya and Appalachian Mountains 27

Plate tectonics produces Earth’s landforms
Tectonics builds mountains Shapes the geography of oceans, islands, and continents Gives rise to earthquakes and volcanoes Determines locations of geothermal energy sources Topography created by tectonics shapes climate Altering patterns of rain, wind, currents, heating, cooling Thereby affecting the locations of biomes Influencing where animals and plants live

The rock cycle Rock cycle = the heating, melting, cooling, breaking, and reassembling of rocks and minerals Rock = any solid aggregation of minerals Mineral = any element or inorganic compound Has a crystal structure, specific chemical composition, and distinct physical properties Rocks help determine soil characteristics Which influences the region’s plants community Helps us appreciate the formation and conservation of soils, minerals, fossil fuels, and other natural resources 29

Igneous rock Magma = molten, liquid rock
Lava = magma released from the lithosphere Igneous rock = forms when magma cools Intrusive igneous rock = magma that cools slowly below Earth’s surface (e.g. granite) Extrusive igneous rock = magma ejected from a volcano (e.g. basalt) 30

Sedimentary rock Sediments = rock particles blown by wind or washed away by water Sedimentary rock = sediments are compacted or cemented (dissolved minerals crystallize and bind together) Sandstone, limestone, shale Lithification = formation of rock (and fossils) through compaction and crystallization 31

Metamorphic rock Metamorphic rock = great heat or pressure on a rock changes its form High temperature reshapes crystals Changing rock’s appearance and physical properties Marble = heated and pressurized limestone Slate = heated and pressurized shale 32

Geologic and natural hazards
Some consequences of plate tectonics are hazardous Plate boundaries closely match the circum-Pacific belt An arc of subduction zones and fault systems Has 90% of earthquakes and 50% of volcanoes

Earthquakes result from movement
Earthquake = a release of energy (pressure) along plate boundaries and faults Can be caused by enhanced geothermal systems Drill deep into rock, fracture it Pump water in to heat, then extract it Can do tremendous damage to life and property Buildings can be built or retrofitted to decrease damage

Volcanoes Volcano= molten rock, hot gas, or ash erupts through Earth’s surface Cooling and creating a mountain In rift valleys, ocean ridges, subduction zones, or hotspots (holes in the crust) Lava can flow slowly or erupt suddenly Pyroclastic flow: fast-moving cloud of gas, ash, and rock Buried Pompeii in A.D. 79

Volcanoes have environmental effects
Ash blocks sunlight Sulfur emissions lead to sulfuric acid Blocking radiation and cooling the atmosphere Large eruptions can decrease temperatures worldwide Mount Tambora’s eruption caused the 1816 “year without a summer” Yellowstone National Park is an ancient supervolcano Past eruptions were so massive they covered much of North America in ash The region is still geologically active

Landslides are a form of mass wasting
Landslide = a severe, sudden mass wasting Large amounts of rock or soil collapse and flow downhill Mass wasting = the downslope movement of soil and rock due to gravity Rains saturate soils and trigger mudslides Erodes unstable hillsides and damages property Caused by humans when soil is loosened or exposed Lahars = extremely dangerous mudslides Caused when volcanic eruptions melt snow Huge volumes of mud race downhill

Tsunamis Tsunami = huge volumes of water are displaced by:
Earthquakes, volcanoes, landslides Can travel thousands of miles across oceans Coral reefs, coastal forests, and wetlands are damaged Saltwater contamination makes it hard to restore them Agencies and nations have increased efforts to give residents advance warning of approaching tsunamis Preserving coral reefs and mangrove forests decreases the wave energy of tsunamis

Dangerous tsunami On March 11, 2011 an earthquake off Japan
15,883 deaths, 2,654 missing and caused a nuclear meltdown of a power plant On December 26, 2004 an earthquake off Sumatra triggered a massive tsunami that hit Indonesia, Thailand, Sri Lanka, India, and African countries Killed 228,000 and displaced 1–2 million more

We can worsen impacts of natural hazards
We face and affect other natural hazards: floods, coastal erosion, wildfire, tornadoes, and hurricanes Overpopulation: people must live in susceptible areas We choose to live in attractive but vulnerable areas (beaches, mountains) Engineered landscapes increase frequency or severity of hazards (damming rivers, suppressing fire, mining) Changing climate through greenhouse gases changes rainfall patterns, increases drought, fire, flooding, storms

We can mitigate impacts of natural hazards
We can decrease impacts of hazards through technology, engineering, and policy Informed by geology and ecology Building earthquake-resistant structures Designing early warning systems (tsunamis, volcanoes) Preserving reefs and shorelines (tsunamis, erosion) Better forestry, agriculture, mining (mass wasting) Regulations, building codes, insurance incentives discourage developing in vulnerable areas Mitigating climate change may reduce natural hazards

Mining Ch 23

Minerals and mining We extract raw minerals from beneath our planet’s surface Turn them into products we use everyday Rock and resources from the lithosphere contribute to our economies and lives Rock = a solid aggregation of minerals Mineral = a naturally occurring solid chemical element or inorganic compound It has a crystal structure, specific chemical composition, and distinct physical properties Minerals are nonrenewable, so we need to be aware of their finite and decreasing supplies

We obtain minerals by mining
We obtain minerals through the process of mining Mining = in the broad sense, it is the extraction of any resource that is nonrenewable We mine minerals, fossil fuels, and groundwater Mining = in relation to minerals, it is the systematic removal of rock, soil, or other material to remove the minerals of economic interest Because minerals occur in low concentrations, concentrated sources must be found before mining

We extract minerals from ores
Metal = an element that is lustrous, opaque, and malleable and can conduct heat and electricity Ore = a mineral or grouping of minerals from which we extract metals Economically valuable metals include copper, iron, lead, gold, aluminum Tantalite ore is mined, processed into tantalum, and used in electronic devices

We process metals after mining ore
Most minerals must be processed after mining After mining the ore, rock is crushed and the metals are isolated by chemical or physical means The material is processed to purify the metal Alloy = a metal is mixed, melted, or fused with another metal or nonmetal substance Steel is an alloy of iron and carbon Smelting = heating ore beyond its melting point then combining it with other metals or chemicals

Processing minerals has costs
Processing minerals has environmental costs Most methods are water- and energy-intensive Chemical reactions and heating to extract metals from ores emit air pollution Tailings = ore left over after metals have been extracted Pollutes soil and water They may contain heavy metals or acids (cyanide, sulfuric acid) Water evaporates from tailings ponds, which may leach pollutants into the environment

We also mine nonmetallic minerals and fuels
Nonmetallic minerals include sand, gravel, phosphates, limestone, and gemstones $7 billion/year of sand and gravel are mined in the U.S. Phosphates provide fertilizer “Blood diamonds” are mined and sold to fund, prolong, and intensify wars in Angola and other areas Substances are mined for fuel Uranium for nuclear power Coal, petroleum, natural gas are not minerals (they are organic), but they are also extracted from the Earth

Mining methods and their impacts
People in developing nations suffer war and exploitation because of the developed world’s appetite for minerals In 2009, raw materials from mining gave $57 billion to the U.S. economy After processing, minerals contributed $454 billion 28,000 Americans were directly employed for mining Large amounts of material are removed during mining Disturbing lots of land Different mining methods are used to extract minerals Economics determines which method to use

Strip mining removes surface soil and rock
Strip mining = layers of soil and rock are removed to expose the resource Overburden = overlying soil and rock that is removed by heavy machinery After extraction, each strip is refilled with the overburden Used for coal, oil sands, sand, gravel Destroys natural communities over large areas and triggers erosion Acid drainage = sulfide minerals form sulfuric acid and flow into waterways

A mining method: subsurface mining
Accesses deep pockets of a mineral through tunnels and shafts The deepest mines are 2.5 mi Zinc, lead, nickel, tin, gold, diamonds, phosphate, salt, coal The most dangerous form of mining Dynamite blasts, collapsed tunnels Toxic fumes and coal dust Acid drainage, polluted groundwater Sinkholes damage roads, homes, etc.

A mining method: open pit mining
Used with evenly distributed minerals Terraced so men and machines can move about Copper, iron, gold, diamonds, coal Quarries = open pits for clay, gravel, sand, stone (limestone, granite, marble, slate) Huge amounts of rock are removed to get small amounts of minerals Habitat loss, aesthetic degradation, acid drainage Abandoned pits fill with toxic water

One open pit mine One Utah mine is 2.5 mi across and 0.75 mi deep; almost half a million tons of ore and rock are removed each day

A mining method: placer mining
Using running water, miners sift through material in riverbeds Coltan miners, California’s Gold Rush of 1849 Used for gold, gems Debris washed into streams makes them uninhabitable for wildlife Disturbs stream banks, causes erosion Harms riparian plant communities

A mining method: mountaintop removal
Entire mountaintops are blasted off The waste is dumped into valleys For coal in the Appalachian Mountains of the eastern U.S. Economically efficient “Valley filling” = dumping rock and debris into valleys Degrades and destroys vast areas Pollutes streams, deforests areas, erosion, mudslides, flash floods An area the size of Delaware has already been removed

Mountaintop removal is socially devastating
Mine blasting cracks foundations and walls Floods and rock slides affect properties Overloaded coal trucks speed down rural roads Coal dust and contaminated water cause illness Local politicians do not help High-efficiency mining reduces the need for workers

A mining method: solution mining
Solution mining (in-situ recovery) = resources in a deep deposit are dissolved in a liquid and siphoned out Salts, lithium, boron, bromine, potash, copper, uranium Less environmental impact than other methods Less surface area is disturbed Acids, heavy metals, uranium can accidentally leak

A mining method: undersea mining
We extract minerals (e.g., magnesium) from seawater Minerals are dredged from the ocean floor Sulfur, phosphate, calcium carbonate (for cement), silica (insulation and glass), copper, zinc, silver, gold Manganese nodules = small, ball-shaped ores scattered across the ocean floor Mining them is currently uneconomical Hydrothermal vents may have gold, silver, zinc Mining would destroy habitats and organisms and release toxic metals that could enter the food chain

Restoration of mined sites
Governments in developed countries require companies to reclaim (restore) surface-mined sites Other nations (e.g., Congo) have no regulations at all Reclamation aims to bring a site to a condition similar to its pre-mining condition Remove structures, replace overburden, replant vegetation The U.S Surface Mining Control and Reclamation Act mandates restoration Companies must post bonds to ensure restoration

Restoration of mined sites
Even on restored sites, impacts may be severe and long-lasting Complex communities are simplified Forests, wetlands, etc. are replaced by grasses Essential symbioses are eliminated and often not restored Water can be reclaimed Remove heavy metals pH is moderated

The General Mining Act of 1872
Encourages metal and mineral mining on federal land Any citizen or company can stake a claim on any public land open to mining for $5 per acre The public gets no payment for any minerals found Once a person owns the land, that land can be developed for any reason, having nothing to do with mining Supporters say it encourages a domestic industry that is risky and provides essential products Critics say it gives land basically free to private interests Efforts to amend the act have failed in Congress

Minerals are nonrenewable and scarce
We must recover and recycle our limited supplies Once known reserves are mined, minerals will be gone For example, indium, used in LCD screens, might only last 32 more years Gallium (for solar power) and platinum (fuel cells) are also scarce Reserve estimates are uncertain New discoveries, technologies, consumption patterns, and recycling affect mineral supplies As minerals become scarcer, demand and price rise

Factors affecting how long deposits last
Discovery of new reserves increases known reserves Minerals worth $900 billion were discovered in Afghanistan in 2010 New extraction technologies reach more minerals at less expense Changing social and technological dynamics modify demand in unpredictable ways Lithium batteries are replacing cadmium-nickel ones Changing consumption patterns affect how fast we exploit reserves (e.g., a recession depresses demand) Recycling extends the lifetimes of minerals

We can use minerals sustainably
Recycling addresses: Finite supplies Environmental damage 35% of metals were recycled in 2008 from U.S. municipal solid waste 7 million tons Steel, iron, platinum, gold, nickel, germanium, tin, and chromium Reduces greenhouse gases by 25 million metric tons

We can recycle rare metals from e-waste
Electronic waste (e-waste) from computers, printers, cell phones, etc. is rapidly rising Recycling keeps hazardous wastes out of landfills while conserving mineral resources 1.2 billion cell phones sold each year contain 200 chemicals and precious metals Phones can be refurbished and resold or dismantled and their parts reused or recycled Only 10% of cell phones are recycled Recycling reduces demand for virgin ores and reduces pressure on ecosystems

Conclusion We depend on minerals and metals to make the products we use Mineral resources are mined by various methods Contributing to material wealth But causing extensive environmental damage (habitat loss, acid drainage, etc.) Restoration and regulations help minimize the environmental and social impacts of mining Maximize recycling and sustainable use of minerals 66

Land Degradation Ch 9:

Population and consumption degrade soil
Feeding the world’s rising human population requires changing our diet or increasing agricultural production But land suitable for farming is running out We must improve the efficiency of food production We must decrease our impact on natural systems Mismanaged agriculture turns grasslands into deserts, removes forests, diminishes biodiversity It also pollutes soil, air, and water with chemicals Fertile soil is blown and washed away

Land degradation and soil conservation
Human activities are limiting productivity by degrading soils in many areas Land degradation = a general deterioration of land, decreasing its productivity and biodiversity Erosion, nutrient depletion, water scarcity, salinization, waterlogging, chemical pollution The soil’s structure and pH change, and it loses organic material

Soil conservation Land degradation is caused by intensive, unsustainable agriculture Also by deforestation and urban development It affects up to one-third of the world’s people

Erosion degrades ecosystems and agriculture
Erosion = removal of material from one place to another By wind or water Deposition = arrival of eroded material at a new location Flowing water deposits nutrient-rich sediment in river valleys and deltas Floodplains are excellent for farming Flood control measures decrease long-term farming productivity Erosion occurs faster than soil is formed It also removes valuable topsoil

Soil erosion is a global problem
Humans are the primary cause of erosion It is occurring at unnaturally high rates In Africa, erosion could reduce crop yields by half over the next 40 years Conservation farming decreases erosion When added to population growth, some describe agriculture’s future as a crisis situation

Desertification reduces productivity
Desertification = a loss of more than 10% productivity Erosion, soil compaction Deforestation and overgrazing Drought, salinization, water depletion Climate change Most prone areas = arid and semiarid lands (drylands)

Desertification has high costs
Desertification affects one-third of the planet’s land area In over 100 countries Endangering food supplies of 1 billion people It costs tens of billions of dollars each year China loses over $6.5 billion/year from overgrazing 80% of land in Kenya is vulnerable to desertification from overgrazing and deforestation Desertification is intensified Degradation forces farmers onto poorer land Farmers reduce fallow periods, so land loses nutrients

The Dust Bowl In late 1800 and early 1900, farmers and ranchers:
Grew wheat, grazed cattle Removed vegetation Dust Bowl = 1930s drought + erosion caused “black blizzards” of sand Thousands of farmers left their land Relied on governmental help to survive

Protecting soil: crop rotation and contour farming
Crop rotation = growing different crops from one year to the next Returns nutrients to soil Prevents erosion, reduces pests Wheat or corn and soybeans Contour farming = plowing perpendicular across a hill Prevents rills and gullies

Protecting soil: terracing and intercropping
Terracing = level platforms cut into steep hillsides This “staircase” contains water Intercropping = planting different crops in alternating bands Increases ground cover Replenishes soil Decreases pests and disease

Protecting soil: shelterbelts and reduced tillage
Shelterbelts (windbreaks) = rows of trees planted along edges of fields Slows the wind Can be combined with intercropping Conservation tillage = reduces the amount of tilling Leaves at least 30% of crop residues in the field No-till farming disturbs the soil even less

Conservation tillage around the world
40% of U.S. farmland uses conservation tillage Also used in Brazil, Argentina, Paraguay To minimize problems: Use green manure (dead plants as fertilizer) Rotate fields with cover crops

Plant cover reduces erosion
Plants anchor soil Move livestock to prevent overgrazing Cut fewer trees in an area Plant vegetation along riverbanks and roadsides China’s huge tree-planting program slows erosion But the monocultures are not ecologically functioning forests

Irrigation: productivity with problems
Irrigation = artificially providing water to support agriculture Unproductive regions become productive farmland Waterlogging = overirrigated soils Water suffocates roots Salinization = the buildup of salts in surface soil layers Worse in arid areas Salinization inhibits production of 20% of irrigated cropland, costing over $11 billion/year

Preventing salinization
It is easier and cheaper to prevent it than fix it Do not plant water-guzzling crops in sensitive areas Irrigate with low-salt water Irrigate efficiently Use only water the crop requires Drip irrigation targets water directly to plants

Fertilizers boost yields but cause problems
Fertilizers = substances containing essential nutrients Inorganic fertilizers = mined or synthetically manufactured mineral supplements Organic fertilizers = the remains or wastes of organisms Manure, crop residues, fresh vegetation Compost = produced when decomposers break down organic matter Applying synthetic fertilizer vs. a “green manure”

Overgrazing causes soil degradation
Overgrazing = too many animals eat too much of the plant cover Impedes plant regrowth Soil is degraded and compacted U.S. government subsidies increase harm Few incentives to protect rangeland 70% of the world’s rangeland is classified as degraded, costing $23.3 billion/year

Effects of overgrazing can be striking
Erosion increases, making it hard for plants to grow Non-native invasive species invade Less palatable to livestock Outcompete native vegetation Grazed plot Ungrazed plot

Agricultural policy Farming can be sustainable
No-till and organic farming, responsible grazing Industrial agriculture places huge demands on the land Degradation occurs slowly But farmers need short-term profits Subsidies encourage cultivation on fragile land Farmers should buy crop insurance instead Ranchers graze cattle extremely cheaply on BLM (Bureau of Land Management) land Environmentalists and ranchers work together against suburban sprawl

U.S. programs promote soil conservation
Conservation Reserve Program (1985): farmers are paid to put highly erodible land in conservation reserves Trees and grasses are planted instead of crops Each dollar spent saves 1 ton of topsoil Generates income for farmers Improves water quality Provides habitat for native wildlife The 2008 farm bill limited reserve lands to 32 million acres But funds 14 other similar land conservation programs

Food Resources Ch 10: ,

Today, we are producing more food per person
By 2050, we will have to feed 9 billion people Food production exceeds population growth We produce food through technology Fossil fuels, irrigation, fertilizer, pesticides, cultivating more land, genetic engineering Today, soils are in decline and most arable land is already farmed

Undernutrition and food security
1 billion people do not have enough to eat Undernutrition = people receive fewer calories than their minimum requirements Due to economics, politics, conflict, and inefficiencies in distribution Most undernourished live in developing nations But 36 million Americans are “food insecure” Food security = guarantee of an adequate, safe, nutritious, and reliable food supply

Food security Undernutrition decreased between 1970 and 1990
Higher food prices (2006–2008) and the economic slump (2008–2009) increased the number and percent of hungry 15% of the world’s population is hungry

Overnutrition and malnutrition
Overnutrition = receiving too many calories each day Developed countries have abundant, cheap junk food, and people lead sedentary lives In the U.S., 25% of adults are obese Worldwide, over 400 million people are obese Malnutrition = a shortage of nutrients the body needs The diet lacks adequate vitamins and minerals Can lead to diseases

Americans spend $42 billion per year trying to lose weight.
In 2020, ¾ of all American adults are going to be either overweight or obese By 2030, according to Johns Hopkins University, it could be 86% Americans spend $42 billion per year trying to lose weight. $24 billion per year is needed to eliminate world hunger.

The Green Revolution increased yields
Spread to the developing world in the 1940s Wheat, rice, corn Depended on lots of: Synthetic fertilizers Chemical pesticides Irrigation Machinery Norman Borlaug: The Father of the Green Revolution “The Man Who Saved A Billion Lives” Norman Borlaug won the Nobel Peace Prize for his work

Consequences of the Green Revolution
From 1900 to 2000, cultivated area increased 33% While energy inputs increased 80 times Positive effects on the environment Prevented some deforestation and land conversion Preserved biodiversity and ecosystems Negative effects on natural resources Pollution, erosion Salinization, desertification

The Green Revolution Intensified agriculture saved millions from starvation Turning India into a grain exporter Rich farmers with lots of land benefited Poor farmers were driven off the land into cities Today, yields are declining in some Green Revolution areas

Monocultures increase output, but at a cost
Monoculture = large expanses of a single crop More efficient, increases output Devastates biodiversity Susceptible to disease and pests Human diet is narrowed: 90% of our food comes from 15 crop and 8 livestock species Armyworms easily destroy monocultures

Biofuels affect food supplies
Biofuels = are derived from organic materials Replace petroleum in engines Ethanol = a biofuel derived from corn 2007 subsidies doubled production Food prices increased Farmers sold corn for ethanol, not food Farmers planted biofuels, not food crops Riots erupted in many nations

Preserving crop diversity: insurance against failure
Preserving native variants protects against crop failure Monocultures are vulnerable Wild relatives contain genes that can provide resistance to disease and pests But Mexico has lifted its ban on transgenic corn We have lost a great deal of genetic diversity in crops U.S. crops have decreased 90% in diversity Market forces discourage diversity in food’s appearance Food producers prefer uniform, standardized food

Seed banks are living museums
Seed banks = institutions that preserve seed types as living museums of genetic diversity Seeds are collected, stored, and periodically planted The “doomsday seed vault” in Norway stores millions of seeds from around the world

Consumption of animal products is growing
As wealth and commerce increase, so does meat, milk, and egg consumption Since 1950, global meat production has increased fivefold and per capita meat consumption has doubled Domestic animals raised for food increased from 7.2 billion in 1961 to 24.9 billion in 2008

Our food choices are also energy choices
Eating meat is far less energy efficient than eating crops 90% of energy is lost from one trophic level to the next Eating lower on the food chain feeds more people Some animals convert grain into meat more efficiently than others Land and water are needed to raise food for livestock Producing eggs and chicken meat requires the least space and water Producing beef requires the most

Feedlot agriculture Feedlots (factory farms) = also called Concentrated Animal Feeding Operations (CAFOs) Huge warehouses or pens deliver food to animals living at extremely high densities Over half of the world’s pork and most of its poultry U.S. farms house hundreds of thousands of debeaked chickens in crowded cages

High consumption leads to feedlot agriculture
Traditional agriculture keeps livestock on grasslands Feedlot animals are fed grain grown on cropland One-third of the world’s cropland is fed to livestock Feedlot agriculture allows economic efficiency Greater production of food Unavoidable in countries with high meat consumption, like the U.S. Reduced grazing impacts on the land Manure can be applied to fields as fertilizer

Livestock agriculture pollutes water and air
Feedlots produce huge amounts of manure and urine Causing eutrophication Waterborne pathogens sicken people Crowded, dirty housing causes outbreaks in disease Heavy use of antibiotics, hormones, heavy metals Chemicals are transferred to people Microbes evolve resistance to antibiotics Air pollution: odors, ammonia (acid rain) More greenhouse gases (CO2, methane, nitrous oxides) than automobile emissions

We raise fish on “fish farms”
World fish populations are plummeting Technology and increased demand Aquaculture = raising aquatic organisms in a controlled environment Species are raised in open-water pens or land-based ponds

Aquaculture is growing rapidly
Over 220 freshwater and marine species are grown The fastest-growing type of food production Provides ¾ of the world’s fish, ½ of the shellfish Most widespread in Asia

The benefits and drawbacks of aquaculture
Diseases require expensive antibiotics Lots of waste Uses grain Escaped GM fish introduce disease or outcompete wild fish Benefits: A reliable protein source Can be sustainable Reduces pressure on overharvested wild fish Energy efficient

Pests and Pesticides Ch 10: ,

Rachel Carson Rachel Carson: an American marine biologist and conservationist whose book Silent Spring and other writings are credited with advancing the global environmental movement. Silent Spring brought environmental concerns to an unprecedented share of the American people. Although Silent Spring was met with fierce opposition by chemical companies, it spurred a reversal in national pesticide policy, which led to a nationwide ban on DDT and other pesticides, and it inspired a grassroots environmental movement that led to the creation of the U.S. Environmental Protection Agency (EPA)

We have thousands of pesticides
Pest = any organism that damages valuable crops Weed = any plant that competes with crops Pesticides = poisons that target pest organisms Insecticides = kill insects Herbicides = kill plants Fungicides = kill fungi 400 million kg (900 million lb) of pesticides are applied in the U.S. each year 75% of this is applied to agricultural land $32 billion/year is spent on pesticides worldwide

Pests evolve resistance to pesticides
Some individuals are genetically immune to a pesticide They pass these genes to their offspring Pesticides stop being effective Pesticide treadmill = chemists increase chemical toxicity to compete with resistant pests Pesticides also kill nontarget organisms Including predators and parasites of pests Pest populations become harder to control

Biological control (biocontrol)
Biological control = uses a pest’s predators to control the pest Reduces pest populations without chemicals Reduces chemical use Cactus moths control prickly pear Bacillus thuringiensis (Bt) = soil bacteria that kills many pests

Biocontrol agents may become pests
It is risky to introduce an organism from a foreign ecosystem into a new ecological context The effects of an introduced species are unpredictable The agent may have “nontarget” effects on the environment and surrounding economies Cactus moths are eating rare Florida cacti Removing a biocontrol agent is harder than halting pesticide use Biocontrol use must be carefully planned and regulated

Second Generation Pesticides
Broad-spectrum agents: Toxic to many species Narrow-spectrum agents: toxic to narrow group of organisms Target species: species pesticide is to act on. Nontarget species: species that is affected as a result of pesticide use and is not intended to be such as beneficial insects

Persistent Organic Pollutants (POPs)
Organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potential significant impacts on human health and the environment. Many POPs are currently or were in the past used as pesticides

Characteristics of POPs
POP exposure can cause death and illnesses including disruption of the endocrine, reproductive, and immune systems; neurobehavioral disorders; and cancers possibly including breast cancer. Exposure to POPs can take place through diet, environmental exposure, or accidents.

Characteristics of an Ideal Pesticide
Kill only target pests Harm no other species Break down quickly Not cause genetic resistance Be more cost-effective than doing nothing

The Case for Pesticides
Save human lives Increase supplies and lower cost of food Increase profits for farmers Work better and faster than alternatives Health risks may be insignificant compared to benefits Newer pesticides are becoming safer New pesticides are used at lower rates

The Case Against Pesticides
Genetic resistance Can kill nontarget and natural control species Can cause an increase in other pest species The pesticide treadmill Pesticides do not stay put Can harm wildlife Potential human health threats

Integrated Pest Management
An ecological approach to pest control uses a mix of cultivation and biological methods, and small amounts of selected chemical pesticides as a last resort. Integrated Pest Management (IPM)

Integrated Pest Management (IPM)
Techniques to suppress pests: Biocontrol Chemicals, if necessary Population monitoring Habitat alteration Crop rotation and transgenic crops Alternative tillage methods Mechanical pest removal IPM in Indonesia increased rice yields 13% and saved $179 million/yr in phased-out subsidies

IPM: A Component of Sustainable Agriculture
Many scientists urge the USDA to use three strategies to promote IPM in the U.S.: Add a 2% sales tax on pesticides. Establish federally supported IPM demonstration project for farmers. Train USDA personnel and county farm agents in IPM. The pesticide industry opposes such measures.

Pesticide Regulation in the United States
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA): established by Congress in 1947 and amended in 1972 it requires the EPA to approve all use of commercial pesticides. All pesticide companies must test their products for toxicity to animals and extrapolate to humans before they can be registered for use. Tolerance levels: level of pesticide residue allowable on fruits and vegetables when a consumer eats it.

Pesticide Regulation in the United States
EPA Evaluation of chemicals: more than 600 active ingredients approved for use in pre 1972 pesticide products are to be reevaluated for cancer, birth defects, or other heath risks. They have only evaluated 10% in over 30 years. Inadequate and poorly enforced: Blame difficulty and expense of determining the health effects of chemicals. Also the falsification of data from a pesticide company that allowed more than 200 pesticide active ingredients to be registered.

Food Quality Protection Act (FQPA
Established in 1996 Requires pesticide companies to verify safety of active ingredients in children and infants Allows 10 fold pesticide tolerance level for infants and children Requires the EPA to consider exposure to more than one pesticide when setting tolerance levels Requires the EPA to develop rules for program to screen for estrogenic and endocrine effects by 1999 (still not accomplished by 2002)

Sustainable agriculture
Industrial agriculture may seem necessary But less-intensive agricultural methods are better Sustainable agriculture = does not deplete soil, pollute water, or decrease genetic diversity Low-input agriculture = uses smaller amounts of pesticide, fertilizers, growth hormones, water, and fossil fuels than industrial agriculture Organic agriculture = uses no synthetic fertilizers, insecticides, fungicides, or herbicides Relies on biological approaches (e.g., composting and biocontrol)

Organic approaches reduce inputs and pollution
Organic Food Production Act (1990) establishes national standards for organic products The USDA issued criteria in 2000 by which food could be labeled organic Some states pass even stricter guidelines for labeling California, Washington, Texas Nearly 500 organizations offer certification services

The benefits of organic farming
Farmers have lower input costs, enhanced income, reduced chemical pollution, and soil degradation They practice stewardship to the land Obstacles include risks and costs of switching to new methods Consumers are concerned about pesticide’s health risks They want to improve environmental quality Obstacles include the higher price of organics

GM Foods Ch 10:

Genetically modified organisms
Genetic engineering = laboratory manipulation of genetic material Add, delete, modify DNA Genetically modified (GM) organisms = organisms that have been genetically engineered by … Recombinant DNA = DNA created from multiple organisms

Biotechnology is impacting our lives
Biotechnology = the application of biological science to create products derived from organisms Transgenic organism = an organism that contains DNA from another species Transgenes = the genes that have moved between organisms Biotechnology has created medicines, cleaned up pollution, and dissolved blood clots

One use for Transgenic plants
Transgenic plants are being created to be resistant to pesticides That way, farmers can blanket fields with a broad spectrum pesticide, killing pests and weeds but not killing the desired crop

Genetic engineering versus agricultural breeding
Traditional breeding = changes organisms through selective breeding of the same or similar species Works with organisms in the field Genes come together on their own Uses the process of selection Genetic engineering = mixes genes of different species Works with genetic material in the lab Directly creates novel combinations of genes Resembles the process of mutation

Biotechnology is changing our world
GM foods are a big business Most GM crops are herbicide and pesticide resistant Large-scale farmers grow crops more efficiently Most U.S. corn, soybeans, cotton, and canola are genetically modified Globally, 14 million farmers grew GM foods on 134 million ha

What are the impacts of GM crops?
As GM crops expanded, scientists, citizens, and policymakers became concerned Impacts on human health Concerns over escaping transgenes They could harm nontarget organisms Bees and butterflies are considered particularly vulnerable Pests could evolve resistance They could ruin the integrity of native ancestral races and interbreed with closely related wild plants

Genetic engineering has benefits and risks
Environmental benefits of genetic engineering: Reduced use of chemical insecticides Increased no-till farming Decreased irrigation, deforestation, land conversion Negatives of genetic engineering: Increased herbicide use affects health and habitats Some GM fields support less biodiversity Precautionary principle = don’t undertake a new action until the effects of that action are understood

The GM debate involves ethics
People don’t like “tinkering” with the food supply Nearly half of Americans feel GM products are unsafe With increasing use, people are forced to use GM products, or go to special effort to avoid them However, laws proposing labels on GMO have been repeatedly voted down Around 70 percent of processed foods in the U.S. contain genetically modified ingredients Multinational corporations threaten the small farmer Research is funded by corporations that profit if GM foods are approved for use GM crops have not eradicated hunger GM crops tend not to focus on increased nutrition, drought tolerance, etc. The GM industry is driven by market considerations driven by financial interests of corporations

Core Case Study: Golden Rice -Grains of Hope or an Illusion?
Golden rice is a new genetically engineered strain of rice containing beta-carotene. Can inexpensively supply vitamin A to malnourished.

Core Case Study: Golden Rice -Grains of Hope or an Illusion?
Critics contend that there are quicker and cheaper ways to supply vitamin A. Scientist call for more evidence that the beta-carotene will be converted to vitamin A by the body. Can the poor buy the new rice? How much beta-carotene will actually be converted to vitamin A? Can it grow well outside of a laboratory? Is this just a ploy to draw support and acceptance for GMOs? Is this drawing attention away from a quicker, cheaper solution? (2 vitamin A pills a year)

GMO producers are suing farmers
Corporations go to great lengths to protect their GM investments Monsanto has launched 112 lawsuits against 372 farmers, winning an average $385,000 per case Monsanto sued Percy Schmeiser of Canada for using its GM seeds without paying for them Schmeiser said the seeds blew onto his field from adjacent fields The courts sided with Monsanto, saying that Schmeiser had violated Monsanto’s patent

The future of GM foods Europeans demand that GM foods are labeled
U.S. consumers have mostly accepted GM crops They don’t realize most food contains GM products The U.S. sued the European for hindering free trade The Cartagena Protocol on Biosafety lays out guidelines for open information about exported crops The U.S. has not joined Brazil, India, and China approve GM crops

6. Food And Soil.

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6. Food And Soil.

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